Can mechanistic constraints on recombination reestablishment explain the long-term maintenance of degenerate sex chromosomes?
Y and W chromosomes often stop recombining and degenerate. Most work on recombination suppression has focused on the mechanisms favoring recombination arrest in the short term. Yet, the long-term maintenance of recombination suppression is critical to evolving degenerate sex chromosomes. This long-t...
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2024-02-01
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| Online Access: | https://peercommunityjournal.org/articles/10.24072/pcjournal.373/ |
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| author | Lenormand, Thomas Roze, Denis |
| author_facet | Lenormand, Thomas Roze, Denis |
| author_sort | Lenormand, Thomas |
| collection | DOAJ |
| description | Y and W chromosomes often stop recombining and degenerate. Most work on recombination suppression has focused on the mechanisms favoring recombination arrest in the short term. Yet, the long-term maintenance of recombination suppression is critical to evolving degenerate sex chromosomes. This long-term maintenance has been little investigated. In the long term, recombination suppression may be maintained for selective reasons (e.g., involving the emergence of nascent dosage compensation), or due to mechanistic constraints preventing the reestablishment of recombination, for instance when complex chromosomal rearrangements evolve on the Y. In this paper, we investigate these ‘constraint’ theories. We show that they face a series of theoretical difficulties: they are not robust to extremely low rates of recombination restoration; they would rather cause population extinction than Y degeneration; they are less efficient at producing a non-recombining and degenerate Y than scenarios adding a selective pressure against recombination, whatever the rate of recombination restoration. Finally, whether such very high constraints exist is questionable. Very low rates of recombination reestablishment are sufficient to prevent Y degeneration, given the large fitness advantage to recover a non-degenerate Y or W for the heterogametic sex. The assumption of a lack of genetic variation to restore recombination seems also implausible given known mechanisms to restore a recombining pair of sex chromosomes. |
| format | Article |
| id | doaj-art-16e26154f12042fe9c01d5f5b29032d7 |
| institution | Kabale University |
| issn | 2804-3871 |
| language | English |
| publishDate | 2024-02-01 |
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| spelling | doaj-art-16e26154f12042fe9c01d5f5b29032d72025-02-07T10:17:18ZengPeer Community InPeer Community Journal2804-38712024-02-01410.24072/pcjournal.37310.24072/pcjournal.373Can mechanistic constraints on recombination reestablishment explain the long-term maintenance of degenerate sex chromosomes? Lenormand, Thomas0https://orcid.org/0000-0001-8930-5393Roze, Denis1CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, FranceCNRS, IRL 3614, Roscoff, France; Sorbonne Université, Station Biologique de Roscoff, Roscoff, FranceY and W chromosomes often stop recombining and degenerate. Most work on recombination suppression has focused on the mechanisms favoring recombination arrest in the short term. Yet, the long-term maintenance of recombination suppression is critical to evolving degenerate sex chromosomes. This long-term maintenance has been little investigated. In the long term, recombination suppression may be maintained for selective reasons (e.g., involving the emergence of nascent dosage compensation), or due to mechanistic constraints preventing the reestablishment of recombination, for instance when complex chromosomal rearrangements evolve on the Y. In this paper, we investigate these ‘constraint’ theories. We show that they face a series of theoretical difficulties: they are not robust to extremely low rates of recombination restoration; they would rather cause population extinction than Y degeneration; they are less efficient at producing a non-recombining and degenerate Y than scenarios adding a selective pressure against recombination, whatever the rate of recombination restoration. Finally, whether such very high constraints exist is questionable. Very low rates of recombination reestablishment are sufficient to prevent Y degeneration, given the large fitness advantage to recover a non-degenerate Y or W for the heterogametic sex. The assumption of a lack of genetic variation to restore recombination seems also implausible given known mechanisms to restore a recombining pair of sex chromosomes.https://peercommunityjournal.org/articles/10.24072/pcjournal.373/inversion, deleterious mutations, extinction, regulatory evolution, XY, ZW |
| spellingShingle | Lenormand, Thomas Roze, Denis Can mechanistic constraints on recombination reestablishment explain the long-term maintenance of degenerate sex chromosomes? Peer Community Journal inversion, deleterious mutations, extinction, regulatory evolution, XY, ZW |
| title | Can mechanistic constraints on recombination reestablishment explain the long-term maintenance of degenerate sex chromosomes?
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| title_full | Can mechanistic constraints on recombination reestablishment explain the long-term maintenance of degenerate sex chromosomes?
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| title_fullStr | Can mechanistic constraints on recombination reestablishment explain the long-term maintenance of degenerate sex chromosomes?
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| title_full_unstemmed | Can mechanistic constraints on recombination reestablishment explain the long-term maintenance of degenerate sex chromosomes?
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| title_short | Can mechanistic constraints on recombination reestablishment explain the long-term maintenance of degenerate sex chromosomes?
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| title_sort | can mechanistic constraints on recombination reestablishment explain the long term maintenance of degenerate sex chromosomes |
| topic | inversion, deleterious mutations, extinction, regulatory evolution, XY, ZW |
| url | https://peercommunityjournal.org/articles/10.24072/pcjournal.373/ |
| work_keys_str_mv | AT lenormandthomas canmechanisticconstraintsonrecombinationreestablishmentexplainthelongtermmaintenanceofdegeneratesexchromosomes AT rozedenis canmechanisticconstraintsonrecombinationreestablishmentexplainthelongtermmaintenanceofdegeneratesexchromosomes |